Future shock has arrived in the District of Columbia police department.

Tomorrow, members of the department's Special Operations Division are scheduled to add to their arsenal a 50,000-volt weapon called a Taser, a handgun the size of a flashlight that temporarily immobilizes suspects by firing electrically-charged darts.

Yesterday the weapon was demonstrated for reporters and police officials from the city and surrounding jurisdictions. The darts were fired into Michael Dinenna, a 250-pound Bethesda bar manager to whom police had paid $250 for the experiment.

When the darts had penetrated his clothing and the outer surface of his skin, Dinenna, 6-foot-7, instantly fell to the floor of the lineup room at police headquarters, a paralyzed lump.

He was able to rise in about 10 seconds, but police could have kept him stunned and on the ground by increasing the current through wires attached to the darts, police said.

Deputy Police Chief Marty M. Tapscott said four of the weapons, costing $200 each, will be deployed by special operations for a six-month trial period. If proved effective, he said, Tasers may eventually be placed in police patrol cars throughout the city.

Tapscott emphasized that the new weapons are not intended to replace service revolvers, but as a device to subdue unruly suspects, while avoiding physical harm to either civilians or police officers.

"I see the use being very selective," Tapscott said. "If no situation came up in six months where we had to use it, then we don't need it."

The Taser is being used by dozens of police departments across the country, with apparent enthusiasm.

Locally police in Fairfax and Prince George's counties have tried the weapon and found it useful in some situations.

Fairfax County police spokesman Capt. Andrew Page said four Tasers have been in use on a test basis since April, and the department is considering ordering seven more, one for each of the county's police substations.

Page said the Tasers have been called into action three times, twice on the same individual. That man, Page said, was a noncooperative "weight-lifter type" whose parents had signed mental commitment papers to have him taken away.

Page said the man was zapped once to get him to the hospital, and then, after being treated and released, he again was ordered commited and he again resisted -- until police approached with the Taser.

"He didn't want to get shot again," Page said.

"If you've ever worked on a car and touched a spark plug while the motor was running, then you know what it feels like," said Prince George's County Police Sgt. Bill Spalding. "It's the same pulsing sensation, only 20 times worse."

Spalding got the Taser's darts in his thigh last year during a demonstration in which he pretended to hold a cocked revolver to the head of a hostage. Both he and the revolver fell to the floor before he could pull the trigger.

Prince George's police have used Tasers to subdue two drug-influenced suspects at the Capitol Centre. On another occasion, while trying to serve commitment papers, Spalding used a Taser on a man who had barricaded himself inside his house with a wooden club.

"It knocked him right out of his house slippers," Spalding said.

Police in Los Angeles have had the use of 80 Tasers for the last year and a half. Department spokesman Pat Connelly said another 300 are being ordered for patrol cars.

The electrical pulse of the 1 1/2-pound Taser is transmitted through tiny wires to the barbed darts up to a range of 15 feet. According to the weapon's developer, California entrepreneur Jack Cover, the Taser acts on the nervous system to cause instant paralysis, but leaves no harmful after-effects.

"I think it's a wonderful weapon," said Gary Hankins, head of the bargaining committee for the Fraternal Order of Police, the labor organization for rank-and-file officers.

"This represents an opportunity for an officer to stop short of using deadly force that he currently doesn't have. It's an opportunity to save lives."